hnswlib

license

Apache-2.0(OSI)

source

public

core features withheld

no

Apache-2.0 license body confirmed. The repository is public and unarchived and builds the whole product, and the README describes no paid tier, enterprise edition or license-gated build beside it, so source is public and the core ungated.

• https://raw.githubusercontent.com/nmslib/hnswlib/master/LICENSE recorded 2026-09-30

  LICENSE file is the Apache-2.0 text: "Apache License" and "Version 2.0, January 2004" and "TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION".

• https://raw.githubusercontent.com/nmslib/hnswlib/master/README.md recorded 2026-09-30

  README describes a "Header-only C++ HNSW implementation with python bindings, insertions and updates." and lists "Lightweight, header-only, no dependencies other than C++ 11"; searched the body for enterprise, paid tier and license key: none.

The hnswlib package on PyPI is this library's own Python distribution, not a client for a different product, so its download count measures hnswlib directly. The package's declared source link happens to point at the maintainer's personal repository rather than nmslib/hnswlib, but that does not change what the downloads count.

• https://pypistats.org/api/packages/hnswlib/recent recorded 2026-08-18

  last_month downloads = 544,320 for hnswlib

hnswlib ships a single index structure, HNSW, as a header-only C++ library with Python bindings supporting insertion, updates and filtered search, with no storage, persistence or query layer of its own. That keeps it two steps below Chroma, which builds a full retrieval system around such an index.

• https://raw.githubusercontent.com/nmslib/hnswlib/master/README.md recorded 2026-09-30

  README documents a header-only C++ HNSW library with "Added support to filtering" and "`save_index(path_to_index)` saves the index from persistence."